Process for isomerizing unsaturated fatty acids or derivatives thereof



PROCESS FOR ISOMERIZING UNSATURATED FATTY ACIDS OR DERIVATIVES THEREGF Johannes Donatus von Mikusch-Buchberg, Hamburg- Harburg, Germany, assignor to Lever Brothers Company, New York, N. Y., a corporation of Maine No Drawing. Application June Serial No. 293,664

Ciainis priority, application Netherlands June 14, 1951 6 Claims. (Cl. 260-4056) This invention relates to a process for treating unsaturated fatty acids or derivatives thereof; for example a process for the improvement of drying and semi-drying oils for use in protective coatings and also to a catalyst for use in the process. In the case of oils, the improvement is accomplished by catalytic conjugation in the presence of a catalyst consisting of nickel supported on a silicon containing carrier and containing minor amounts of selenium and/ or tellurium and/ or sulphur.

Many processes have been suggested for isomerizing, drying and semi-drying oils such as linseed and soyabean oils with the objective of producing a substitute for tung oil or improving the drying properties of the semi-drying oils such as soyabean oil, in order to provide a substitute for linseed oil. The known methods of conjugation have included alkali isomerization, isomerization with sulphur dioxide, isomerization with iodide compounds, isomerization with nickel-carbon catalysts and treatment with tertiary butyl hypochlorite followed by dechlorination.

All of the known processes suffer from the disadvantage in that dried films of the isomerized oils remain tacky, and the high temperatures required for isomerization cause a considerable amount of polymerization which reduces the versatility of the oils.

A known method of preparing nickel isomerization catalysts is to heat and precipitate nickel out of a solution of a nickel compound on silicon dioxide containing substances such as kieselguhr or sodium silicate using an alkaline compound such as sodium hydroxide. The precipitate of nickel on the carrier is then dried and reduced in an atmosphere of hydrogen. A small amount of sulphur may be added in one of several forms to the catalyst cake during preparation and before reduction thereof.

The known nickel catalysts have proved suitable for the isomerization of unsaturated fatty acids or their derivatives such as the methyl esters or triglycerides or of those substances containing unsaturated fatty acids or their derivatives. The treatment of fatty oils with these catalysts is of particular importance. They can be treated either in their crude condition or after pre-treatment, for example, after neutralizing and bleaching. Examples of such oils are drying or semi-drying oils and non-drying oils containing oleic acid or other single unsaturated fatty acid radicals. Examples of other compounds which can be treated in this manner are unsaturated fatty acids such as oleic acid, linseed oil fatty acids and alkyl esters, for example, the ethyl esters. Mixtures of these compounds and mixtures containing the aforementioned unsaturated compounds can also be treated.

in the case of oils used in the paint industry, the treatment is advantageous in that the oils retain a light color and acquire a high content of conjugated double bonds so that they quickly polymerize and rapidly dry into non-tacky waterproof films. The specific gravity, viscosity, and free fatty acid content are virtually unchanged after the treatment.

Generally speaking, treatment of compounds of the type above listed results in a shifting of the positions of atent 2,746,979 Fatented May 22,

the double bonds and simultaneous conversion of the cisisomers into the transform. In the case of unsaturated fatty acids or their derivatives with more than one double bond, the principal effect is the conjugation of the double bonds. In the refining of unsaturated fatty acids or their derivatives with a single double bond, for example, oleic acid or its esters, the principal reaction is the conversion from the cis into the transform. As a result of the treatment, the melting point is raised. A small amount of polymerization occurs concurrently with the conjugation of the double bonds.

It has now been found that a superior catalyst is obtained if a minor amount, e.g. several percent, of selenium and/ or tellurium is added to the catalyst. The selenium or tellurium may be added in any of their allotropic forms. Thus, selenium may be added in the grey ormetallic form and in the red form, while the tellurium may be added in the tin-white form and the brown form. Also, the selenium or tellurium may be added in the form of compounds. Thus, selenites and tellurites such as for example CaSeOs, CuSeOs, NaHSeOs, NaH3(SeO3)2, CaOZSeOz, CaOxTeOz and NazOxTeOz, in which x may be 1, 2, 4 or 6, may be added. Selenates and tellurates, for example, B38604, CaSeOi, NaHTeO4, CaTeOr and Cai'iiTeO may be added. The selenium and/or tellurium is added to the catalyst before the reduction step.

It is also advantageous to add to the catalyst, in addition to selenium and/or tellurium, a small amount of sulphur, for example, 1 to 2% calculated on the basis of nickel. It is particularly advantageous to add sulphur to catalysts having a smaller selenium and/or tellurium content.

The amount of nickel which may be supported on the carrier may vary from 50% by weight to 300% by weight of the support and the total amount of nickel in the catalyst may vary from 30% by weight to by weight.

The quantity of selenium or tellurium which may be incorporated in the catalyst is variable. Good results have been obtained incorporating 4 to 12% of metallic selenium or tellurium calculated on the basis of nickel, but larger or smaller quantities display activity.

The carrier for the catalyst may be any well-known silicon dioxide containing substance such as kieselguhr, sodium silicate, and the like.

The nickel catalyst is prepared by precipitating nickel on to a carrier from a nickel nitrate or other solution using an alkaline reagent such as sodium carbonate or other alkali. The nickel is precipitated on to the carrier in the form of alkaline nickel carbonate. Preferably, the precipitated nickel carbonate is boiled for a further period in the sodium carbonate solution. The carrier and precipitated nickel carbonate are filtered from the solution and a quantity of selenium, tellurium or a compound of one of these elements is added before reduction of the catalyst cake. The selenium and/or tcllurium can be added to the catalyst cake while it is still moist, or to the solution either before, during or after precipitation of the nickel compound. The dry catalyst cake containing the. desired amount of selenium and/or teliurium is reduced by heating in a current of hydrogen.

In isomerizing an oil, the reduced catalyst is introduced into the oil, which should preferably be as free from peroxides as possible, without permitting the catalyst to come in contact with the air. This may be accomplished by introducing the catalyst in a carbonic acid atmosphere, for example.

The amount of catalyst used in isomerization is variable and may be between 0.2% and 10% by weight calculated on the basis of nickel to oil. A preferable range is 1 to 4% by weight of catalyst calculated on the basis of nickel to oil.

The isomerization temperature may be in the range of 3 80 to 220 C. and a preferred range is about 120 to 160? C. The isomerization reaction occurs more rapidly at higher temperatures, but at temperatures above 220 C., undesired side reaction become excessive. Good results are obtained by treating the oils for a short period of time, for example, 5 to 30 minutes, at 200 to 220 C.

The duration of the treatment is dependent upon the reaction temperature and the quantity of catalyst em ployed and also upon the degree of isomerization desired. Generally speaking, maximum isomerization or conjugation can be obtained in from about 2 to hours. In order to ascertain when the reaction is complete, the refractive index or the pandiene value of the conjugated bonds is determined by testing during treatment. When these values cease to increase, the reaction is complete. The catalyst may be separated from the isomerized product by filtration and may be used repeatedly until it becomes inactive.

The invention will be further illustrated by reference to the following examples. In these examples reference is made to the pandiene value of an oil. This value is explained in Angewandte Chemie, vol. 62, 1950, pages 4'15 to 480.

EXAMPLE 1 295 grams Ni(NO3)2.6H2O were dissolved in 600 cc. of water. 30 grams of kieselguhr was added and the solution was brought to boiling temperature while stirring. 350 grams of Na2CO3.10H2O dissolved in 720 cc. of water was then slowly added to the boiling solution. After the mixed solutions were boiled for one-half hour, they were filtered and the precipitate was washed with water.

T l precipitate was dried in the air and divided into portions and varying quantities of metallic selenium calculated on the basis of nickel were mixed with the separate portions. These separate portions containing varying quantities of selenium are shown in the table below. The separate catalyst portions were reduced by heating for one hour in a hydrogen current at 475 C.

The separate catalyst portions, after being first cooled under hydrogen, and then under carbon dioxide were introduced into separate, portions of an oil to be isomerized.

The oil used was linseed oil and each portion was treated at 140 C. for 4 hours with 4% by Weight of the catalyst, calculated on the basis of nickel to oil,'prepared according to Example 1 above, which contained varying quantities ofv selenium as shown in the first column of the. table below:

xi. slowly added to the first solution over a period of 1 /2 hours.

The mixed solutions were boiled for one-half hour, filtered, and the precipitate was washed with water until no turbulence was detected using a barium chloride solution. The precipitate was dried in the air and divided into parts with which were mixed different quantities of metallic selenium calculated on a nickel basis, as shown in Table II below, after which the precipitate was reduced for one hour at 475 C. in a hydrogen current. The cataiyst, after being cooled under hydrogen and then under carbon dioxide, was introduced into the oil to be isomerised under carbon dioxide.

The oil isomerized was linseed oil and was treated for 4 hours at 140 C. using 4% by weight of the catalyst calculated on a nickel to oil basis. The catalyst was prepared in accordance with the procedure of Example 2 above and also contained 1.7% sulphur. The following increases in the refractive index were noted:

Table II Rise of refractive index after 4 hours Percentage by weight; of selenium to nickel.-

Table III Rise of refractive index after 4 hours Percentage by weight of suplhur to nickel EXAMPLE 3 The following results were obtained using a catalyst, prepared in accordance with the procedure of Example 2 above, which contained 4% selenium calculated on a nickel, basis.

A neutralized soyabean oil was treated for 4 hours at Table I 140 C. with 4% by weight of the catalyst calculated on a nickel to oil basis. The soyabean oil possessed the following constants before and after isomerization: Rise of the Colour L oyibond Percentage by weight of refractive am' (1 selenium to nickel index after g Before After 4 hours yellow l red 1 un t acid number 0.0112 38 10 0.6 saponlflcatlon number... 0. 0143 4 1 1- l Woburn-lodine number. 0-0154 52 23, 2.0 115 value 83%33 a a e r e n 1.. 020160 51 27 on our( ov.l 2 e ow, 0.1 e 1 e ow, e 0.0140 44 20 2.0 0-0110 38 12 L0 From the pandiene value of 46.6, a conjugated fatty 1 Initial oil Yellow 4, red 0.4.

With equivalent quantities of sulphur, considerably poorer results are achieved. For example, 2.4% sulphur,

equivalent to 6% selenium, gives rise in the refractive index of only 0.0130.

EXAMPLE 2 acid glyceride content in the product of approximately 54.5% can be calculated.

The soyabean oil treated in this manner dries after siccativation with 0.3% lead and 0.03% cobalt in 45 minutes at 40- C. to a practically non-tacky film while soyabean oil is similarly siccativated but not treatedin accordance with the; invention requires five hours to dry under similar conditions and then tends to be. tacky.

EXAMPLE 4 A tobacco seed oil neutralized with lye was isomerized using 4% by weight of the catalyst of Example 2 above, calculated on anickel to oil basis, for 4 hours at C.

Before After 72, 1.4848. acid number 21 0.34. saponification number 190. Wooum-iodine number 148.1 diene value t. 44.6. pandlene value..- "5

m1 colour 1 Lov 12 Yellow, 1 Red.

From the pandiene value of the product of 52.75, a conjugated glyceride content in the oil of 61% can be calculated.

EXAMPLE 5 Safiiower oil neutralized with lye was isomerized for four hours at 140 C. with 4% of the catalyst of Example 2, calculated on a nickel to oil basis. The catalyst contained 4% selenium calculated on a nickel basis. The constants before and after the treatment were:

I Before After 11,, "l 1.4756 1.4845 acid number 0.55 0.26. saponification number 192.1 191.9. Woburn-iodine number 144.3" 147.5. diene value 32.0. paudiene valuc. 9

3 .9. colour Luv. 1 2Yellow, 1 Re 20 Yellow, 1 Red.

From the pandiene value of 39.9 a conjugated product content of approximately 46% can be calculated.

EXAMPLE 6 A poppy-seed oil neutralized with lye was treated with 4% by weight of the catalyst of Example 2, calculated on a nickel to oil basis, for 4 hours at 140 C. The catalyst contained 4% selenium calculated on a nickel basis. The constants before and after the treatment were:

Before After 11 1.4808 acid number 0.62. saponification numb 189.5 Woburn-iodine number. 132.4 (liene value 24.4.

pandiene value... colour Lov. 1" 6 Yellow, 0.6 Red...

EXAMPLE 7 Linseed oil was treated for 4 hours at 140 C. with 2.5% by weight of a catalyst, calculated on a nickel to 011 basis, prepared in accordance with Example 2 above. The catalyst contained 2.5 %selenium calculated on a nickel basis. At the end of the treatment, the refractive index had risen by 0.0142.

EXAMPLE 8 EXAMPLE 9 A dry nickel carbonate cake prepared in accordance with Example 2 above was mixed with 4% powdered tellurium, calculated on a nickel basis, and the catalyst was then reduced in accordance with the procedure of Example 2.

39.5. 16 Yellow, 2 Red.

A gum-free neutralized linseed oil was treated. for 4 hours at 140 C. with 4% by weight of this catalyst calculated as nickel to oil. The refractive index rose from an initial value of n =l.4780 to a terminal value of 1.4912, showing an increase of 0.0132.

EXAMPLE 10 A nickelcarbonate cake prepared in accordance with Example 2 above was mixed with sufficient copper selenite so that the cake contained 3% selenium calculated on a nickel basis, after which the cake was reduced in accordance with Example 2.

A gum-free, neutralized linseed oil was treated for four hours at 140 C. using 4% by weight of the catalyst, calculated on a nickel to oil basis, and the refractive index rose by 0.0159.

I claim:

1. The method of isomerizing a substance selected from the group consisting of unsaturated fatty acids and the ester and glyceride derivatives thereof comprising contacting said substance with a supported catalyst comprising a major portion of nickel and a minor portion of an element selected from the group consisting of selenium and tellurium at a temperature in the range from about C. to about 220 C. for a period from about five minutes to about ten hours.

2. The method of isomerizing a substance selected from the group of unsaturated fatty acids and the ester and glyceride derivatives thereof comprising contacting said substance with a supported catalyst comprising a major portion of nickel and from about 4% to about 12% by Weight, calculated on a nickel basis, of an element selected from the group consisting of selenium and tellurium at a temperature in the range from about 80 C. to about 220 C. for a period from about five minutes to about ten hours.

3. The method of isomerizing a substance selected from the group consisting of unsaturated fatty acids and the ester and glyceride derivatives thereof comprising contacting said substance with a supported catalyst comprising a major portion of nickel, from about 4% to about 12% by weight, calculated on a nickel basis, of an element selected from the group consisting of selenium and tellurium, and from about 1% to about 2% by weight of sulfur, calculated on a nickel basis, at a temperature in the range from about 80 C. to about 220 C. for a period from about five minutes to about ten hours.

4. The method of isomerizing a substance selected from the group consisting of unsaturated fatty acids and the ester and glyceride derivatives thereof comprising contacting said substance with a catalyst comprising a major portion of nickel and a minor portion of an element selected from the group consisting of selenium and tellurium, said catalyst being supported upon a silicon dioxide containing carrier, at a temperature in the range from about 80 C. to about 220 C. for a period from about five minutes to about ten hours.

5. The method of isomerizing a substance selected from the group consisting of unsaturated fatty acids and the ester and glyceride derivatives thereof comprising contacting said substance with a catalyst comprising a major portion of nickel and from about 4% to about 12% by weight, calculated on a nickel basis, of an element selected from the group consisting of selenium and tellurium, said catalyst being supported upon a silicon dioxide containing a carrier, at a temperature in the range from about 80 C. to about 220 C. for a period from about five minutes to about ten hours.

6. The method of isomerizing a substance selected from the group consisting of unsaturated fatty acids and the ester and glyceride derivatives thereof comprising contacting said substance with a catalyst comprising a major portion of nickel, from about 4% to about 12% by weight, calculated on a nickel basis, of an element selected from the group consisting of selenium and tellurium, and from about 1% to about 2% by weight of sulfur, calculated on a nickel basis, said catalyst being supported upon a silicon dioxide containing carrier, at a temperature in the range from about 80 C. to about 220 C. for a period from about five minutes to about 5 ten hours.

References Cited in the file of this patent UNITED STATES PATENTS 10 1,955,829 Pier et al Apr. 24, 1934 8 Jackson July 30, 1935 La Lande June 6, 1939 Archibald et a1. Oct. 12, 1943 Colgate Oct. 3, 1944 Corson May 17, 1949 Radlove Mar. 28, 1950 Stejskal July 4, 1950 Stejskal May 15, 1951 FOREIGN PATENTS Great Britain July 8, 1953 

1. THE METHOD OF ISOMERIZING A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF UNSATURATED FATTY ACIDS AND THE ESTER AND GLYCERIDE DERIVATIVES THEREOF COMPRISING CONTACTING SAID SUBSTANCE WITH A SUPPORTED CATALYST COMPRISING A MAJOR PORTION OF NICKEL AND A MINOR PORTION OF AN ELEMENT SELECTED FROM THE GROUP CONSISTING OF SELENIUM AND TELLURIUM AT A TEMPERATURE IN THE RANGE FROM ABOUT 80* C. TO ABOUT 220* C. FOR A PERIOD FROM ABOUT FIVE MINUTES TO ABOUT TEN HOURS. 